Electric-arc lamp



(No Model.)

S. P. PARMLY.

ELECTRIC ARC LAMP.

No. 540,800. Patented June 11, 1895.

J a A J I! M 1 w@ L1-.- fiQ Z A J w s C p E F Uerrrnn STATES PATENT Fries.

SAMUEL P. PARMLY, OF CHICAGO, ILLINOIS.

ELECTRIC-ARC LAMP.

SPECIFICATION forming part of Letters Patent No. 540,800, dated June 11, 1895.

Application filed October 26, 1891, Serial No. 409,941. (No model.)

To aZZ whom it may concern.-

Be it known that I, SAMUEL P. PARMLY, a citizen of the United States, residing at Chi cago, in the county of Cook and State of Illinois, have invented a new and useful Im provementin Arc Lamps, of which the following is a specification.

My invention relates to are lights and has for its object to provide a double service or long burning arc lamp which shallcontain but a single pair of electrodes and shall possess certain advantages with reference to the establishment and maintenance of the arc and with regard to preventing, shadows in the light as hereinafter set out. It is illustrated in the accompanying drawings, wherein Figure 1 is a side view of the lamp provided with carbons as proposed by me. Fig. 2 is a detail of one form of carbon. Fig. 3 is a de' tail of another form; Fig. 4, of still another form; Fig. 5, of still another form; Fig. 6, of still another form.

The groups here illustrated are each of them in the general form of an ellipse in cross section or a plate having such a cross-section as would constitute a form having a width substantially one-half its length. The cross-sectional area of these groups is also substantially equal to twice the cross-sectional area of an ordinary round carbon having a diameter equal to the width of the cross-section of my proposed carbon.

A is a case containing the operating mechanism of the lamp.

B B are the side bars; O, the upper carbon rod to which the carbon D is attached; E, the lower carbon rod held in the carbon holder F.

G is a carbon substantially elliptical in crosssection. H is a similar carbon with angular edges.

J is a carbon right angle in cross section.

L is a carbon diamond-shaped in cross-section; and M is a carbon elliptical in crosssection.

The preferred form of carbon is substantially that shown in Figs. 1, 2 and 6, or in other words, a carbon substantially elliptical in cross-section and having a cross-section whose width is substantially one-half of its length with rounded or flattened ends. The

central transverse diameter may be extended or shortened, as, for example, in the two forms shown in Figs. 2 and 6.

I have found by a long course of experi ments that where a carbon formed substantially as suggested is employed in a lamp and placed in opposition to a similar carbon, the

tendency is to burn in something like the form indicated in Fig. 1, and also that both carbons or electrodes retain a continuously heated end so that as the arc travels along the-opposed edges, which it must do, there is no occasion for it to attack cold material, and hence it is possible to keep a comparatively uniform arc although the same travels back and forth across the edge of the opposed electrode.

A satisfactory arc is obtained without material localization by a construction of electrodes in which the arc is permitted to travel back and forth. The rounded edges of the carbon are not, of course, indispensable, as with the square cornered form shown in Fig. 4 a somewhat similar result is obtained, but it is attended with some irregularity of the are and also with greater shadow, and hence is not the preferred form. Nor is it indispensable that the carbons should have the precise cross-section indicated, as roughened, grooved or corrugated sides might be used where the grooving or the corrugating is insufficient to prevent the operation of the lamp as hereinbefore described and provided forthat is to say,such change of form would not take a device out of the scope of my invention so long as such changed form of carbon permitted the arc to travel back and forth Without material or substantial localization thereof.

Any of these several forms of carbons shown can be used either with a similar carbon above or below or with any other form of carbon above or below. Many other forms of carbons could easily be devised which would be in effect the same as those here illustrated. These several forms, however, when so used keep the arc in motion for the most part and to a very great degree avoid localization of the are.

I claim- 1. A pair of carbon pencils for an electric arc lamp burning the pencils by holding them in line end to end and having a feed mechanism adapted to adjust the pencils toward one another as they are consumed formed each with a total cross sectional area approximately twice that of the round carbons ordinarily employed on a circuit carrying the same curto end and to be adjusted toward one another as they are consumed by an arc passing between them each offsaid pencils having across sectional area substantially twice the cross sectional area of thezordinary round carbon and substantially in the'form of a flattened bar with thickness and width as one to two and rounded or flattened along its edges.

In an electric arc lamp burning its carbons end to end and provided with means for feeding them toward one another as they are consumed by theme, pencils or electrodes formed each as a flattened bar or prism thickest at the middle and becoming thinner toward the edges and having a total cross sectional area approximately twice that of the round carbon ordinarily employed on a circdit carrying the same current.

4. A pair of carbon pencils for an electric arc lamp burning two and only two pencils by holding them in line end to end and having a feed mechanism adapted toadjust the pencils toward one another as they are consumed, said pencils having each a transverse area double that of the ordinary cylindrical lamp carbons commonly employed on circuits carrying the same number of ampres, and at least one of them formed as a flattened bar or prism of a thickness approximately equal to the diameter-of the ordinary cylindricalsingle lamp carbon and of a width approximately twice its thickness and tapered or thinned from its middle toward its edge.

5. A pair of carbon pencils for an electric arc lamp adapted to be presented to one another end to end and to be adjusted toward one another as they are consumed by an are passing between them, formed each with an elliptical or oval figure in'cross section the minor diameter of which is approximately that of the round carbon ordinarily employed on a circuit having the same current while its major diameter is sufficient to give the increased mass in cross section required to di- 53 minish the rate of consumption to the desired degree.

6. A pair of carbon pencils for an arc lamp adapted to be presented to one another end to end and to be adjusted toward one another as they are consumed by an are passing between them, formed each as a flattened bar or prism thickest at the middle and becoming thinner toward the edges as and for the purposes described. I

7. A pair of carbon pencils foran arc lamp adapted to be presented to one another end to end and to be adjusted toward one another as they are consumed by an are passing between them, formed each with an elliptical or oval figure in cross section, as and for the purpose described.

8. A pair of carbon pencils for an arc lamp adapted to be presented to one another end to end and to be adjusted toward one another as they are consumed by an are passing between them,each of said pencils having a cross-sectional area substantially twice the cross-sectional area of the ordinary round carbon and substantially in the form of a flattened bar with-thickness and width as one to two.

9. A pair of carbon pencils for an arc lamp adapted to be presented to one another end to end and to be adjusted toward one another as they are consumed by an are passing between them, each of said pencils having a cross sectional area substantially twice the cross-sectional area of the ordinary round 'carbon for the same current, and with a long diameter substantially twice the diameter of of an ordinary round carbon for the same current, and shaped so that the arc travels back and forth without material localization.

SAMUEL P. PARMLY. Witnesses:

O. P. CHAPMAN, WALTER J. GUNTHORP. 

